T to the explosive day in court at the see-called breakup murder trial. The prosecutor grilling a psychologist for jodi arias' defense and raising serious questions about his testimony. Abc's ryan owens has the story. You don't know that, do you? No, I don't. I'm speculating. Reporter: This psychologist could have used some therapy by the time prosecutor juan martinez got done with him. Made it up. Speculated. Reporter: Dr. Richard samuels diagnosed jodi arias with posttraumatic stress disorder and killing her ex-boyfriend was so stressful on her, she can't remember it. I have no memory of stabbing him. Reporter: But the psychologist admits arias lied to him. Back then she was saying two intruders murdered alexander and later admitted she killed him but claims it was in self-defense. She experienced the trauma even though she was telling the story different from what happened so this test reflects her internal struggle, her internal emotional state and in my opinion is perfectly valid. Reporter: But martinez would have none of it. He accused dr. Samuels of being a hired gun who didn't administer the test correctly. For $250 an hour you say you weren't paying enough attention to put whatever else was needed on -- I reviewed the report numerous times and must admit i missed it. Reporter: Then misinterpreted the results to help the defense. The 75 doesn't mean anything. Right, it doesn't mean anything, that's why they threw it in there, right? You're misinterpreting -- I studied these tests for years. Reporter: The prosecutor believes arias planned the brutal murder of her ex and is pretending she doesn't remember to keep her off death row. When the doctor was unclear about something martinez took the opportunity to ask him the question he asked arias countless times. Do you have any problems with your memory? No, I do not have problems with my memory. Reporter: Samuels will be back on the stand to answer more questions this time from the jurors who will decide jodi arias' fate. For "good morning america," ryan owens, abc news, phoenix.

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